A diversion dam is a dam that diverts all or a portion of the flow of a river from its natural course. Diversion dams do not generally impound water in a reservoir. Instead, the water is diverted into an artificial water course or canal, which may be used for irrigation or return to the river after passing through hydroelectricgenerators, flow into a different river or be itself dammed forming a reservoir.

An early diversion dam is the Ancient EgyptianSadd el-Kafara Dam at Wadi Al-Garawi, which was located about twenty five kilometres south of Cairo. Built around 2600 BC for flood control, the structure was 102 metres long at its base and eighty seven metres wide, it was destroyed by a flood while it was still under construction.[1][2]

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Diversion dams are one of three classifications of dams which include: storage dams, detention dams, and diversion dams. Storage dams are used to store water for extended lengths of time, the stored water then can be used for irrigation, livestock, municipal water supply, recreation, and hydroelectric power generation. Detention dams are built to catch surface runoff to prevent floods and trap sediment by regulating the flow rate of the runoff into channels downstream. Diversion dams are used to raise the water level in order to redirect the water to the designated location, the diverted water can be used for supplying irrigation systems or reservoirs.[3]

Diversion dams are installed to raise the water level of a body of water to allow the water to be redirected, the redirected water can be used to supply irrigation systems, reservoirs, or hydroelectric power generation facilities. The water diverted by the diversion dam to the reservoirs can be used for industrial applications or for municipal water supply.[3]

Embankment style diversion dams are constructed to counteract the force of the water pushing on the dam by building a dam with enough weight to withstand the force. Embankment dams are commonly made from materials in the surrounding area where the dam is being built, the materials generally include: sand, gravel, and rocks. The combination of these building materials with either clay or an impervious membrane gives the embankment dam its integrity, as a result, the combination of its simple construction and locally available building materials the cost of building an embankment dam is lower than the other types of dams.[3]

Buttress style diversion dams are designed using angle supports on the downstream side of the dam, the supports are fixed to the wall of the dam in order to help counteract the force of the water on the dam. Buttress style dams are built across wide valleys that do not have a solid bedrock foundation.[3] Bedrock is solid rock that makes up the upper part of the earth’s crust. Bedrock can be made from sedimentary, igneous, and metaphoric rock origins.[4] Buttress dams require extensive steel framework and labor, as a result, buttress style dams are expensive to construct and are seldom built today.[3]

Arch style diversion dams are designed using an arch shape with the top of the arch facing upstream, the arch shape provides extra strength to counteract the force of the water. Arch style dams are generally constructed in narrow canyons. Arch style dams are commonly made from concrete. To ensure the dam’s integrity, a solid contact between the bedrock foundation and the dam’s concrete base is required, the dome style dam is a type of arch dam. The dome style dam curves in both the horizontal plane and vertical plane, the arch style dam only curves in the horizontal.[3]

Gravity style diversion dams are built to non counteract the force of the water pushing on the dam by building a dam with enough weight to withstand the force. Gravity dams are commonly constructed using masonry or cement, the foundations of the gravity dams are generally constructed on top of a solid bedrock foundation. However, gravity dams can be built over unconsolidated ground as long as proper measures are put in place to stop the flow of water under the dam. If water were to get under the dam, the dam could fail.[3]

1.
Clackamas River
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The Clackamas River is an approximately 83-mile tributary of the Willamette River in northwestern Oregon, in the United States. The river rises in eastern Marion County, about 55 miles east-southeast of Salem, the headwaters are on the slopes of Olallie Butte in the Mount Hood National Forest, about 10 miles north of Mount Jefferson, at an elevation of 4,909 feet in the Cascade Range. The Clackamas flows briefly north and then flows northwest through the mountains, passing through North Fork Reservoir and it then emerges from the mountains southeast of Portland. It joins the Willamette near Oregon City and forms the boundary between Oregon City and Gladstone and this environment also allowed Native Americans to settle in the rivers basin as early as 10,000 years ago. Regulation of the began in 1905 with the Cazadero Dam. In 1912, the River Mill Dam intercepted wood and coarse sediment, later dams at North Fork, Oak Grove, Stone Creek, and Timothy Lake also intercepted wood sediment on the lower river. The Clackamas River arises on the slopes of the Cascade Range near Olallie Butte. Flowing generally northwest and then west for about 83 miles, it joins the Willamette River at Gladstone, the river falls nearly 4,900 feet between its source and its mouth. Originating in Marion County, the Clackamas River receives Squirrel Creek from the left bank, about 61 miles from the mouth, Granite Creek enters from the left, and the river flows by Austin Hot Springs and Picnic Area. Shortly thereafter, Switch Creek enters from the right, and at about 57 miles from the mouth, at the confluence, Two Rivers Picnic Area is on the left and Riverford Campground is on the right. About 1 mile further downstream, Trout Creek enters from the left, shortly thereafter, Tag Creek enters from the right, and at about 53 miles from the mouth, the Clackamas River receives Oak Grove Fork Clackamas River from the right. From its confluence with Oak Grove Fork, the river close to Oregon Route 224 for most of the rest of its course. The highway is north and east of the river, that is. It receives Three Lynx Creek and Deer Creek from the right, Cat Creek from the left, soon Pup Creek enters from the left opposite the Sunstrip Campground before Roaring River enters from the right at about 44 miles from the mouth. Near this point, Roaring River Campground is on the right, shortly thereafter, Murphy Creek enters from the right, and Fish Creek enters from the left about 42 miles from the mouth. Over the next few miles, the river flows by Fish Creek Campground and Armstrong Campground, the river then passes Lockaby Campground and Carter Bridge Campground, where it passes under Route 224 again for the fourth and final time. From here to near Gladstone, the river flows south and west of the highway, around 35 miles from the mouth, the river receives the South Fork Clackamas River from the left opposite a landform known as Big Cliff. About 2 miles later, the river enters North Fork Reservoir, the Clackamas reaches the Faraday Dam, formerly known as the Cazadero Dam, about 28 miles from the mouth and passes Faraday Lake, which is on the rivers left about 2 miles later

Clackamas River
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Clackamas River Bridge at Oregon City
Clackamas River
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Clackamas River flowing through Milo McIver State Park
Clackamas River
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Whitewater on the Clackamas River as seen from Highway 224 at Carter Bridge
Clackamas River
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Clackamas River near Austin Point

2.
Hydroelectricity
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Hydroelectricity is electricity produced from hydropower. In 2015 hydropower generated 16. 6% of the total electricity and 70% of all renewable electricity. Hydropower is produced in 150 countries, with the Asia-Pacific region generating 33 percent of global hydropower in 2013, China is the largest hydroelectricity producer, with 920 TWh of production in 2013, representing 16.9 percent of domestic electricity use. The cost of hydroelectricity is relatively low, making it a source of renewable electricity. The hydro station consumes no water, unlike coal or gas plants, the average cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U. S. cents per kilowatt-hour. With a dam and reservoir it is also a source of electricity since the amount produced by the station can be changed up or down very quickly to adapt to changing energy demands. Once a hydroelectric complex is constructed, the project produces no direct waste, Hydropower has been used since ancient times to grind flour and perform other tasks. In the mid-1770s, French engineer Bernard Forest de Bélidor published Architecture Hydraulique which described vertical-, by the late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand for the Industrial Revolution would drive development as well, in 1878 the worlds first hydroelectric power scheme was developed at Cragside in Northumberland, England by William George Armstrong. It was used to power an arc lamp in his art gallery. The old Schoelkopf Power Station No.1 near Niagara Falls in the U. S. side began to produce electricity in 1881. The first Edison hydroelectric power station, the Vulcan Street Plant, began operating September 30,1882, in Appleton, Wisconsin, by 1886 there were 45 hydroelectric power stations in the U. S. and Canada. By 1889 there were 200 in the U. S. alone, at the beginning of the 20th century, many small hydroelectric power stations were being constructed by commercial companies in mountains near metropolitan areas. Grenoble, France held the International Exhibition of Hydropower and Tourism with over one million visitors, by 1920 as 40% of the power produced in the United States was hydroelectric, the Federal Power Act was enacted into law. The Act created the Federal Power Commission to regulate hydroelectric power stations on federal land, as the power stations became larger, their associated dams developed additional purposes to include flood control, irrigation and navigation. Federal funding became necessary for development and federally owned corporations, such as the Tennessee Valley Authority. Hydroelectric power stations continued to become larger throughout the 20th century, Hydropower was referred to as white coal for its power and plenty. Hoover Dams initial 1,345 MW power station was the worlds largest hydroelectric station in 1936

Hydroelectricity
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The Three Gorges Dam in Central China is the world's largest power producing facilitiy of any kind.
Hydroelectricity
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Museum Hydroelectric power plant ″Under the Town″ in Serbia, built in 1900.
Hydroelectricity
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Turbine row at Los Nihuiles Power Station in Mendoza, Argentina

3.
Dam
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A dam is a barrier that impounds water or underground streams. Reservoirs created by not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture. Hydropower is often used in conjunction with dams to generate electricity, a dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. The word dam can be traced back to Middle English, and before that, from Middle Dutch, the first known appearance of dam occurs in 1165. However, there is one village, Obdam, that is mentioned in 1120. The word seems to be related to the Greek word taphos, so the word should be understood as dike from dug out earth. The names of more than 40 places from the Middle Dutch era such as Amsterdam and Rotterdam, early dam building took place in Mesopotamia and the Middle East. Dams were used to control the level, for Mesopotamias weather affected the Tigris. The earliest known dam is the Jawa Dam in Jordan,100 kilometres northeast of the capital Amman and this gravity dam featured an originally 9-metre-high and 1 m-wide stone wall, supported by a 50 m-wide earth rampart. The structure is dated to 3000 BC, the Ancient Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, located about 25 km south of Cairo, was 102 m long at its base and 87 m wide. The structure was built around 2800 or 2600 BC as a dam for flood control. During the Twelfth Dynasty in the 19th century BC, the Pharaohs Senosert III, Amenemhat III, two dams called Ha-Uar running east-west were built to retain water during the annual flood and then release it to surrounding lands. The lake called Mer-wer or Lake Moeris covered 1,700 km2 and is today as Berkat Qaroun. One of the wonders of the ancient world was the Great Dam of Marib in Yemen. Repairs were carried out during various periods, most important around 750 BC and these extensive works were not actually finalized until 325 AD and allowed the irrigation of 25,000 acres. By the mid-late 3rd century BC, an intricate water-management system within Dholavira in modern-day India was built, the system included 16 reservoirs, dams and various channels for collecting water and storing it. Eflatun Pınar is a Hittite dam and spring temple near Konya and it is thought to be from the time of the Hittite empire between the 15th and 13th century BC

4.
Imperial Dam
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The Imperial Diversion Dam is a concrete slab and buttress, ogee weir structure across the California/Arizona border,18 miles northeast of Yuma. Between 1932 and 1940, the Imperial Irrigation District relied on the Inter-California Canal, the Imperial Dam was built with three sections, the gates of each section hold back the water to help divert the water towards the desilting plant. The water is now directed back towards one of the three sections which divert the water one of the three channels. About 90% of the volume of the Colorado River is diverted into the canals at this location, diversions can top 40,000 cubic feet per second, roughly the volume of the Susquehanna River and more than 50 times the flow of the Rio Grande. U. S. Geological Survey Geographic Names Information System, Imperial Dam From the Colorado River to the Salton Sea, The story of Imperial Valleys Water

5.
Colorado River
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The Colorado River is one of the principal rivers of the Southwestern United States and northern Mexico. The 1, 450-mile-long Colorado River drains an expansive, arid watershed that encompasses parts of seven U. S. starting in the central Rocky Mountains in the U. S. After entering Mexico, the Colorado approaches the mostly dry Colorado River Delta at the tip of the Gulf of California between Baja California and Sonora. Known for its dramatic canyons, whitewater rapids, and eleven U. S. National Parks, the Colorados large flow and steep gradient are used for generating hydroelectric power, and its major dams regulate peaking power demands in much of the Intermountain West. Intensive water consumption has dried up the lower 100 miles of the river, beginning with small bands of nomadic hunter-gatherers, Native Americans have inhabited the Colorado River basin for at least 8,000 years. Most native peoples that inhabit the basin today are descended from groups that settled in the region beginning about 1,000 years ago. Europeans first entered the Colorado Basin in the 16th century, when explorers from Spain began mapping and claiming the area, early contact between Europeans and Native Americans was generally limited to the fur trade in the headwaters and sporadic trade interactions along the lower river. After most of the Colorado River basin became part of the U. S. in 1846, several expeditions charted the Colorado in the mid-19th century – one of which, led by John Wesley Powell, was the first to run the rapids of the Grand Canyon. American explorers collected valuable information that would later be used to develop the river for navigation, lesser numbers settled in the upper basin, which was the scene of major gold strikes in the 1860s and 1870s. Large engineering works began around the start of the 20th century, with guidelines established in a series of international. The U. S. federal government was the driving force behind the construction of dams and aqueducts in the river system, although many state. Most of the dams in the river basin were built between 1910 and 1970, the system keystone, Hoover Dam, was completed in 1935. The Colorado is now considered among the most controlled and litigated rivers in the world, as demands for Colorado River water continue to rise, the level of human development and control of the river continues to generate controversy. The Colorado begins at La Poudre Pass in the Southern Rocky Mountains of Colorado, after a short run south, the river turns west below Grand Lake, the largest natural lake in the state. As it flows southwest, it gains strength from many tributaries, as well as larger ones including the Blue, Eagle. In a few areas, such as the marshy Kawuneeche Valley near the headwaters, arcing northwest, the Colorado begins to cut across the eponymous Colorado Plateau, a vast area of high desert centered at the Four Corners of the southwestern United States. In Utah, the Colorado flows primarily through the slickrock country and this is one of the most inaccessible regions of the continental United States. Here, the San Juan River, carrying runoff from the slope of Colorados San Juan Mountains, joins the Colorado from the east. S

6.
River
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A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water, small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the term river as applied to geographic features. Many names for small rivers are specific to geographic location, examples are run in parts of the United States, burn in Scotland and northeast England. Sometimes a river is defined as being larger than a creek, but not always, Rivers are part of the hydrological cycle. Potamology is the study of rivers while limnology is the study of inland waters in general. Extraterrestrial rivers of liquid hydrocarbons have recently found on Titan. Channels may indicate past rivers on other planets, specifically outflow channels on Mars and rivers are theorised to exist on planets, a river begins at a source, follows a path called a course, and ends at a mouth or mouths. The water in a river is confined to a channel. In larger rivers there is also a wider floodplain shaped by flood-waters over-topping the channel. Floodplains may be wide in relation to the size of the river channel. This distinction between river channel and floodplain can be blurred, especially in areas where the floodplain of a river channel can become greatly developed by housing. Rivers can flow down mountains, through valleys or along plains, the term upriver refers to the direction towards the source of the river, i. e. against the direction of flow. Likewise, the term describes the direction towards the mouth of the river. The term left bank refers to the bank in the direction of flow. The river channel typically contains a stream of water, but some rivers flow as several interconnecting streams of water. Extensive braided rivers are now found in only a few regions worldwide and they also occur on peneplains and some of the larger river deltas. Anastamosing rivers are similar to braided rivers and are quite rare

River
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Melting toe of Athabasca Glacier, Jasper National Park, Alberta, Canada
River
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The River Cam from the Green Dragon Bridge, Cambridge (United Kingdom)
River
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Nile River delta, as seen from Earth orbit. The Nile is an example of a wave-dominated delta that has the classic Greek letter delta (Δ) shape after which river deltas were named.
River
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A radar image of a 400-kilometre (250 mi) river of methane and ethane near the north pole of Saturn's moon Titan

7.
Reservoir
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A reservoir is a storage space for fluids. These fluids may be water, hydrocarbons or gas, a reservoir usually means an enlarged natural or artificial lake, storage pond or impoundment created using a dam or lock to store water. Reservoirs can be created by controlling a stream that drains a body of water. They can also be constructed in river valleys using a dam, alternately, a reservoir can be built by excavating flat ground or constructing retaining walls and levees. Tank reservoirs store liquids or gases in storage tanks that may be elevated, at grade level, tank reservoirs for water are also called cisterns. Underground reservoirs are used to store liquids, principally either water or petroleum, a dam constructed in a valley relies on the natural topography to provide most of the basin of the reservoir. Dams are typically located at a part of a valley downstream of a natural basin. The valley sides act as walls, with the dam located at the narrowest practical point to provide strength. In many reservoir construction projects, people have to be moved and re-housed, construction of a reservoir in a valley will usually need the river to be diverted during part of the build, often through a temporary tunnel or by-pass channel. In hilly regions, reservoirs are constructed by enlarging existing lakes. Sometimes in such reservoirs the new top water level exceeds the height on one or more of the feeder streams such as at Llyn Clywedog in Mid Wales. In such cases additional side dams are required to contain the reservoir, where water is pumped or siphoned from a river of variable quality or quantity, bank-side reservoirs may be built to store the water. Such reservoirs are usually formed partly by excavation and partly by building a complete encircling bund or embankment, the water stored in such reservoirs may stay there for several months, during which time normal biological processes may substantially reduce many contaminants and almost eliminate any turbidity. The use of reservoirs also allows water abstraction to be stopped for some time. Service reservoirs store fully treated potable water close to the point of distribution, many service reservoirs are constructed as water towers, often as elevated structures on concrete pillars where the landscape is relatively flat. Other service reservoirs can be almost entirely underground, especially in hilly or mountainous country. In the United Kingdom, Thames Water has many underground reservoirs, sometimes called cisterns, built in the 1800s. A good example is the Honor Oak Reservoir in London, constructed between 1901 and 1909, when it was completed it was said to be the largest brick built underground reservoir in the world and it is still one of the largest in Europe

8.
Canal
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Canals and navigations are human-made channels for water conveyance, or to service water transport vehicles. In the vernacular, both are referred to as canals, and in most cases, the works will have a series of dams. These areas are referred to as water levels, often just called levels. In contrast, a canal cuts across a drainage divide atop a ridge, many canals have been built at elevations towering over valleys and others water ways crossing far below. Cities need a lot of water and many canals with sources of water at a higher level can deliver water to a destination where there is a lack of water. The Roman Empires Aqueducts were such water supply canals, a navigation is a series of channels that run roughly parallel to the valley and stream bed of an unimproved river. A navigation always shares the drainage basin of the river, a vessel uses the calm parts of the river itself as well as improvements, traversing the same changes in height. A true canal is a channel that cuts across a drainage divide, most commercially important canals of the first half of the 19th century were a little of each, using rivers in long stretches, and divide crossing canals in others. This is true for many canals still in use, there are two broad types of canal, Waterways, canals and navigations used for carrying vessels transporting goods and people. These can be subdivided into two kinds, Those connecting existing lakes, rivers, other canals or seas and oceans and those connected in a city network, such as the Canal Grande and others of Venice Italy, the gracht of Amsterdam, and the waterways of Bangkok. Aqueducts, water canals that are used for the conveyance and delivery of potable water for human consumption, municipal uses, hydro power canals. Historically canals were of importance to commerce and the development, growth. In 1855 the Lehigh Canal carried over 1.2 million tons of burning anthracite coal, by the 1930s the company which built. By the early 1880s, canals which had little ability to compete with rail transport, were off the map. In the next couple of decades, coal was diminished as the heating fuel of choice by oil. Later, after World War I when motor-trucks came into their own, Canals are built in one of three ways, or a combination of the three, depending on available water and available path, Human made streams A canal can be created where no stream presently exists. Either the body of the canal is dug or the sides of the canal are created by making dykes or levees by piling dirt, stone, the water for the canal must be provided from an external source, like streams or reservoirs. Where the new waterway must change elevation engineering works like locks, lifts or elevators are constructed to raise, examples include canals that connect valleys over a higher body of land, like Canal du Midi, Canal de Briare and the Panama Canal

Canal
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The Alter Strom, in the sea resort of Warnemünde, Germany.
Canal
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The Royal Canal in Ireland.
Canal
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Small boat canals such as the Basingstoke Canal fueled the industrial revolution in much of Europe and the United States.
Canal
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Loading Anthracite on the Lehigh Canal to feed the early United States industries in the pioneer-era.

9.
Irrigation
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Irrigation is the method in which a controlled amount of water is supplied to plants at regular intervals for agriculture. It is used to assist in the growing of crops, maintenance of landscapes. Additionally, irrigation also has a few uses in crop production. In contrast, agriculture that only on direct rainfall is referred to as rain-fed or dry land farming. Irrigation systems are used for dust suppression, disposal of sewage. Irrigation is often studied together with drainage, which is the natural or artificial removal of surface and sub-surface water from a given area, Irrigation has been a central feature of agriculture for over 5,000 years and is the product of many cultures. Historically, it was the basis for economies and societies across the globe, archaeological investigation has found evidence of irrigation where the natural rainfall was insufficient to support crops for rainfed agriculture. Ancient Egyptians practiced Basin irrigation using the flooding of the Nile to inundate land plots which had surrounded by dykes. The flood water was held until the sediment had settled before the surplus was returned to the watercourse. The Ancient Nubians developed a form of irrigation by using a device called a sakia. Irrigation began in Nubia some time between the third and second millennium BCE and it largely depended upon the flood waters that would flow through the Nile River and other rivers in what is now the Sudan. In sub-Saharan Africa irrigation reached the Niger River region cultures and civilizations by the first or second millennium BCE and was based on wet season flooding, terrace irrigation is evidenced in pre-Columbian America, early Syria, India, and China. These canals are the earliest record of irrigation in the New World, traces of a canal possibly dating from the 5th millennium BCE were found under the 4th millennium canal. Large scale agriculture was practiced and a network of canals was used for the purpose of irrigation. Ancient Persia as far back as the 6th millennium BCE, where barley was grown in areas where the rainfall was insufficient to support such a crop. The Qanats, developed in ancient Persia in about 800 BCE, are among the oldest known irrigation methods still in use today and they are now found in Asia, the Middle East and North Africa. The system comprises a network of wells and gently sloping tunnels driven into the sides of cliffs. The noria, a wheel with clay pots around the rim powered by the flow of the stream, was first brought into use at about this time

10.
Electric generator
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In electricity generation, a generator is a device that converts mechanical energy to electrical energy for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines, the first electromagnetic generator, the Faraday disk, was built in 1831 by British scientist Michael Faraday. Generators provide nearly all of the power for electric power grids, the reverse conversion of electrical energy into mechanical energy is done by an electric motor, and motors and generators have many similarities. Many motors can be driven to generate electricity and frequently make acceptable manual generators. Electromagnetic generators fall into one of two categories, dynamos and alternators. The magnetic field of the dynamo or alternator can be provided by either wire windings called field coils or permanent magnets, a generator using permanent magnets is sometimes called a magneto. Armature, The power-producing component of an electrical machine, in a generator, alternator, or dynamo the armature windings generate the electric current, which provides power to an external circuit. The armature can be on either the rotor or the stator, depending on the design, before the connection between magnetism and electricity was discovered, electrostatic generators were invented. They operated on electrostatic principles, by using moving electrically charged belts, plates, the charge was generated using either of two mechanisms, electrostatic induction or the triboelectric effect. Such generators generated very high voltage and low current and their only practical applications were to power early X-ray tubes, and later in some atomic particle accelerators. The operating principle of electromagnetic generators was discovered in the years of 1831–1832 by Michael Faraday, the principle later called Faradays law, is that an electromotive force is generated in an electrical conductor which encircles a varying magnetic flux. He also built the first electromagnetic generator, called the Faraday disk and it produced a small DC voltage. This design was inefficient, due to self-cancelling counterflows of current in regions of the disk that were not under the influence of the magnetic field. While current was induced directly underneath the magnet, the current would circulate backwards in regions that were outside the influence of the magnetic field and this counterflow limited the power output to the pickup wires, and induced waste heating of the copper disc. Later homopolar generators would solve this problem by using an array of magnets arranged around the perimeter to maintain a steady field effect in one current-flow direction. Another disadvantage was that the voltage was very low, due to the single current path through the magnetic flux. Experimenters found that using multiple turns of wire in a coil could produce higher, since the output voltage is proportional to the number of turns, generators could be easily designed to produce any desired voltage by varying the number of turns. Wire windings became a feature of all subsequent generator designs

Electric generator
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U.S. NRC image of a modern steam turbine generator (STG).
Electric generator
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Early Ganz Generator in Zwevegem, West Flanders, Belgium
Electric generator
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The Faraday disk was the first electric generator. The horseshoe-shaped magnet (A) created a magnetic field through the disk (D). When the disk was turned, this induced an electric current radially outward from the center toward the rim. The current flowed out through the sliding spring contact m, through the external circuit, and back into the center of the disk through the axle.
Electric generator
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This large belt-driven high-current dynamo produced 310 amperes at 7 volts. Dynamos are no longer used due to the size and complexity of the commutator needed for high power applications.

11.
Ancient Egypt
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Ancient Egypt was a civilization of ancient Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. It is one of six civilizations to arise independently, Egyptian civilization followed prehistoric Egypt and coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh Narmer. In the aftermath of Alexander the Greats death, one of his generals, Ptolemy Soter and this Greek Ptolemaic Kingdom ruled Egypt until 30 BC, when, under Cleopatra, it fell to the Roman Empire and became a Roman province. The success of ancient Egyptian civilization came partly from its ability to adapt to the conditions of the Nile River valley for agriculture, the predictable flooding and controlled irrigation of the fertile valley produced surplus crops, which supported a more dense population, and social development and culture. Its art and architecture were widely copied, and its antiquities carried off to far corners of the world and its monumental ruins have inspired the imaginations of travelers and writers for centuries. The Nile has been the lifeline of its region for much of human history, nomadic modern human hunter-gatherers began living in the Nile valley through the end of the Middle Pleistocene some 120,000 years ago. By the late Paleolithic period, the climate of Northern Africa became increasingly hot and dry. In Predynastic and Early Dynastic times, the Egyptian climate was less arid than it is today. Large regions of Egypt were covered in treed savanna and traversed by herds of grazing ungulates, foliage and fauna were far more prolific in all environs and the Nile region supported large populations of waterfowl. Hunting would have been common for Egyptians, and this is also the period when many animals were first domesticated. The largest of these cultures in upper Egypt was the Badari, which probably originated in the Western Desert, it was known for its high quality ceramics, stone tools. The Badari was followed by the Amratian and Gerzeh cultures, which brought a number of technological improvements, as early as the Naqada I Period, predynastic Egyptians imported obsidian from Ethiopia, used to shape blades and other objects from flakes. In Naqada II times, early evidence exists of contact with the Near East, particularly Canaan, establishing a power center at Hierakonpolis, and later at Abydos, Naqada III leaders expanded their control of Egypt northwards along the Nile. They also traded with Nubia to the south, the oases of the desert to the west. Royal Nubian burials at Qustul produced artifacts bearing the oldest-known examples of Egyptian dynastic symbols, such as the crown of Egypt. They also developed a ceramic glaze known as faience, which was used well into the Roman Period to decorate cups, amulets, and figurines. During the last predynastic phase, the Naqada culture began using written symbols that eventually were developed into a system of hieroglyphs for writing the ancient Egyptian language. The Early Dynastic Period was approximately contemporary to the early Sumerian-Akkadian civilisation of Mesopotamia, the third-century BC Egyptian priest Manetho grouped the long line of pharaohs from Menes to his own time into 30 dynasties, a system still used today

Ancient Egypt
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The Great Sphinx and the pyramids of Giza are among the most recognizable symbols of the civilization of ancient Egypt.
Ancient Egypt
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A typical Naqada II jar decorated with gazelles. (Predynastic Period)
Ancient Egypt
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The Narmer Palette depicts the unification of the Two Lands.

12.
Cairo
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Cairo is the capital and largest city of Egypt. Cairo has long been a center of the political and cultural life. Cairo has the oldest and largest film and music industries in the Arab world, as well as the worlds second-oldest institution of higher learning, Al-Azhar University. Many international media, businesses, and organizations have regional headquarters in the city, with a population of 6.76 million spread over 453 square kilometers, Cairo is by far the largest city in Egypt. An additional 9.5 million inhabitants live in proximity to the city. Cairo, like many other mega-cities, suffers from high levels of pollution, Cairos metro, one of only two in Africa, ranks among the fifteen busiest in the world, with over 1 billion annual passenger rides. The economy of Cairo was ranked first in the Middle East in 2005, Egyptians often refer to Cairo as Maṣr, the Egyptian Arabic name for Egypt itself, emphasizing the citys importance for the country. In Coptic the city is known as Kahire, meaning Place of the Sun, possibly referring to the ancient city of Heliopolis, the location of the ancient city is the suburb of Ain Shams. The ancient Egyptian name for the area is thought to be Khere-Ohe, The Place of Combat, sometimes the city is informally referred to as Kayro. The area around present-day Cairo, especially Memphis, had long been a point of Ancient Egypt due to its strategic location just upstream from the Nile Delta. However, the origins of the city are generally traced back to a series of settlements in the first millennium. Around the turn of the 4th century, as Memphis was continuing to decline in importance and this fortress, known as Babylon, remained the nucleus of the Roman, and, later, the Byzantine, city and is the oldest structure in the city today. It is also situated at the nucleus of the Coptic Orthodox community, many of Cairos oldest Coptic churches, including the Hanging Church, are located along the fortress walls in a section of the city known as Coptic Cairo. Following the Muslim conquest in 640 AD the conqueror Amr ibn As settled to the north of the Babylon in an area became known as al-Fustat. Originally a tented camp Fustat became a permanent settlement and the first capital of Islamic Egypt, in 750, following the overthrow of the Ummayad caliphate by the Abbasids, the new rulers created their own settlement to the northeast of Fustat which became their capital. This was known as al-Askar as it was laid out like a military camp, a rebellion in 869 by Ahmad ibn Tulun led to the abandonment of Al Askar and the building of another settlement, which became the seat of government. This was al-Qattai, to the north of Fustat and closer to the river, Al Qattai was centred around a palace and ceremonial mosque, now known as the Mosque of ibn Tulun. In 905 the Abbasids re-asserted control of the country and their returned to Fustat

Cairo
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Cairo القاهرة al-Qāhirah
Cairo
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Louis Comfort Tiffany (American, 1848-1933). On the Way between Old and New Cairo, Citadel Mosque of Mohammed Ali, and Tombs of the Mamelukes, 1872. Oil on canvas. Brooklyn Museum
Cairo
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A rendition of Fustat from A. S. Rappoport's History of Egypt
Cairo
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Cairo map 1847

13.
Livestock
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Livestock are domesticated animals raised in an agricultural setting to produce commodities such as food, fiber, and labor. The term is used to refer solely to those raised for food. In recent years, some organizations have also raised livestock to promote the survival of rare breeds, animal husbandry practices have varied widely across cultures and time periods. Originally, livestock were not confined by fences or enclosures, but these practices have largely shifted to intensive animal farming and these practices increase yield of the various commercial outputs, but have led to increased concerns about animal welfare and environmental impact. Livestock production continues to play an economic and cultural role in numerous rural communities. Livestock as a word was first used between 1650 and 1660, as a merger between the live and stock. Older English sources, such as the King James Version of the Bible, the word cattle is derived from Old North French catel, which meant all kinds of movable personal property, including livestock, which was differentiated from immovable real estate. In later English, sometimes smaller livestock such as chickens and pigs were referred to as small cattle, today, the modern meaning of cattle, without a modifier, usually refers to domesticated bovines, but sometimes livestock refers only to this subgroup. Legal definition United States federal legislation sometimes more narrowly defines the term to make specified agricultural commodities either eligible or ineligible for a program or activity, for example, the Livestock Mandatory Reporting Act of 1999 defines livestock only as cattle, swine, and sheep. Animal-rearing originated during the transition to settled farming communities from hunter-gatherer lifestyles. Animals are domesticated when their breeding and living conditions are controlled by humans, over time, the collective behaviour, lifecycle and physiology of livestock have changed radically. Many modern farm animals are unsuited to life in the wild, dogs were domesticated in East Asia about 15,000 years ago. Goats and sheep were domesticated around 8000 BC in Asia, swine or pigs were domesticated by 7000 BC in the Middle East and China. The earliest evidence of horse domestication dates to around 4000 BC, the term livestock is nebulous and may be defined narrowly or broadly. Broadly, livestock refers to any breed or population of animal kept by humans for a useful and this can mean domestic animals, semidomestic animals, or captive wild animals. Semidomesticated refers to animals which are only lightly domesticated or of disputed status and these populations may also be in the process of domestication. Some people may use the term livestock to refer to only used for red meat. Livestock are used by humans for a variety of purposes, many of which have an economic value, Livestock products include, Meat A useful form of dietary protein and energy, meat is the edible tissue of the animal carcass

14.
Hydroelectric power
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Hydroelectricity is electricity produced from hydropower. In 2015 hydropower generated 16. 6% of the total electricity and 70% of all renewable electricity. Hydropower is produced in 150 countries, with the Asia-Pacific region generating 33 percent of global hydropower in 2013, China is the largest hydroelectricity producer, with 920 TWh of production in 2013, representing 16.9 percent of domestic electricity use. The cost of hydroelectricity is relatively low, making it a source of renewable electricity. The hydro station consumes no water, unlike coal or gas plants, the average cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U. S. cents per kilowatt-hour. With a dam and reservoir it is also a source of electricity since the amount produced by the station can be changed up or down very quickly to adapt to changing energy demands. Once a hydroelectric complex is constructed, the project produces no direct waste, Hydropower has been used since ancient times to grind flour and perform other tasks. In the mid-1770s, French engineer Bernard Forest de Bélidor published Architecture Hydraulique which described vertical-, by the late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand for the Industrial Revolution would drive development as well, in 1878 the worlds first hydroelectric power scheme was developed at Cragside in Northumberland, England by William George Armstrong. It was used to power an arc lamp in his art gallery. The old Schoelkopf Power Station No.1 near Niagara Falls in the U. S. side began to produce electricity in 1881. The first Edison hydroelectric power station, the Vulcan Street Plant, began operating September 30,1882, in Appleton, Wisconsin, by 1886 there were 45 hydroelectric power stations in the U. S. and Canada. By 1889 there were 200 in the U. S. alone, at the beginning of the 20th century, many small hydroelectric power stations were being constructed by commercial companies in mountains near metropolitan areas. Grenoble, France held the International Exhibition of Hydropower and Tourism with over one million visitors, by 1920 as 40% of the power produced in the United States was hydroelectric, the Federal Power Act was enacted into law. The Act created the Federal Power Commission to regulate hydroelectric power stations on federal land, as the power stations became larger, their associated dams developed additional purposes to include flood control, irrigation and navigation. Federal funding became necessary for development and federally owned corporations, such as the Tennessee Valley Authority. Hydroelectric power stations continued to become larger throughout the 20th century, Hydropower was referred to as white coal for its power and plenty. Hoover Dams initial 1,345 MW power station was the worlds largest hydroelectric station in 1936

Hydroelectric power
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The Three Gorges Dam in Central China is the world's largest power producing facilitiy of any kind.
Hydroelectric power
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Museum Hydroelectric power plant ″Under the Town″ in Serbia, built in 1900.
Hydroelectric power
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Turbine row at Los Nihuiles Power Station in Mendoza, Argentina

15.
Reservoirs
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A reservoir is a storage space for fluids. These fluids may be water, hydrocarbons or gas, a reservoir usually means an enlarged natural or artificial lake, storage pond or impoundment created using a dam or lock to store water. Reservoirs can be created by controlling a stream that drains a body of water. They can also be constructed in river valleys using a dam, alternately, a reservoir can be built by excavating flat ground or constructing retaining walls and levees. Tank reservoirs store liquids or gases in storage tanks that may be elevated, at grade level, tank reservoirs for water are also called cisterns. Underground reservoirs are used to store liquids, principally either water or petroleum, a dam constructed in a valley relies on the natural topography to provide most of the basin of the reservoir. Dams are typically located at a part of a valley downstream of a natural basin. The valley sides act as walls, with the dam located at the narrowest practical point to provide strength. In many reservoir construction projects, people have to be moved and re-housed, construction of a reservoir in a valley will usually need the river to be diverted during part of the build, often through a temporary tunnel or by-pass channel. In hilly regions, reservoirs are constructed by enlarging existing lakes. Sometimes in such reservoirs the new top water level exceeds the height on one or more of the feeder streams such as at Llyn Clywedog in Mid Wales. In such cases additional side dams are required to contain the reservoir, where water is pumped or siphoned from a river of variable quality or quantity, bank-side reservoirs may be built to store the water. Such reservoirs are usually formed partly by excavation and partly by building a complete encircling bund or embankment, the water stored in such reservoirs may stay there for several months, during which time normal biological processes may substantially reduce many contaminants and almost eliminate any turbidity. The use of reservoirs also allows water abstraction to be stopped for some time. Service reservoirs store fully treated potable water close to the point of distribution, many service reservoirs are constructed as water towers, often as elevated structures on concrete pillars where the landscape is relatively flat. Other service reservoirs can be almost entirely underground, especially in hilly or mountainous country. In the United Kingdom, Thames Water has many underground reservoirs, sometimes called cisterns, built in the 1800s. A good example is the Honor Oak Reservoir in London, constructed between 1901 and 1909, when it was completed it was said to be the largest brick built underground reservoir in the world and it is still one of the largest in Europe

16.
Embankment dam
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An embankment dam is a large artificial dam. It is typically created by the placement and compaction of a complex semi-plastic mound of various compositions of soil, sand, clay and it has a semi-pervious waterproof natural covering for its surface and a dense, impervious core. This makes such a dam impervious to surface or seepage erosion, such a dam is composed of fragmented independent material particles. The friction and interaction of particles binds the particles together into a stable mass rather than by the use of a cementing substance, embankment dams come in two types, the earth-filled dam made of compacted earth, and the rock-filled dam. A cross-section of an embankment dam shows a shape like a bank, most have a central section or core composed of an impermeable material to stop water from seeping through the dam. The core can be of clay, concrete, or asphalt concrete and this dam type is a good choice for sites with wide valleys. They can be built on rock or softer soils. For a rock-fill dam, rock-fill is blasted using explosives to break the rock, additionally, the rock pieces may need to be crushed into smaller grades to get the right range of size for use in an embankment dam. The building of a dam and the filling of the reservoir behind it places a new weight on the floor, the stress of the water increases linearly with its depth. Thus the stress level of the dam must be calculated in advance of building to ensure that its break level threshold is not exceeded, overtopping or overflow of an embankment dam beyond its spillway capacity will cause its eventual failure. The erosion of the material by overtopping runoff will remove masses of material whose weight holds the dam in place. Even a small sustained overtopping flow can remove thousands of tons of soil from the mass of the dam within hours. As the mass of the dam erodes, the force exerted by the reservoir begins to move the entire structure, therefore, safety requirements for the spillway are high, and require it to be capable of containing a maximum flood stage. It is common for its specifications to be such that it can contain a five hundred year flood. Recently a number of embankment dam overtopping protection systems have been developed

17.
Arch dam
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An arch dam is a concrete dam that is curved upstream in plan. An arch dam is most suitable for narrow gorges or canyons with steep walls of rock to support the structure. Since they are thinner than any other dam type, they require much less construction material, Arch dams classified with respect to their structural height are, Low dams up to 100 feet, Medium high dams between 100–300 ft, High dams over 300 ft. The first known arch dam, the Glanum Dam, also known as the Vallon de Baume Dam, was built by the Romans in France, the dam was about 12 metres high and 18 metres in length. Its radius was about 14 m, and it consisted of two masonry walls, the Romans built it to supply nearby Glanum with water. The Monte Novo Dam in Portugal was another early arch dam built by the Romans in 300 AD and it was 5.7 metres high and 52 m long, with a radius of 19 m. The curved ends of the dam met with two winged walls that were supported by two buttresses. The dam also contained two water outlets to drive mills downstream, the Mongols also built arch dams in modern-day Iran. Their earliest was the Kebar Dam built around 1300, which was 26 m high and 55 m long and their second dam was built around 1350 and is called the Kurit Dam. After 4 m was added to the dam in 1850, it became 64 m tall, the Kurit Dam was of masonry design and built in a very narrow canyon. The canyon was so narrow that its crest length is only 44% of its height, the dam is still erect, even though part of its lower downstream face fell off. The Elche Dam in Elche, Spain was an arch dam built in the 1630s by Joanes del Temple. The dam was 26 metres high and 75 metres long, and had a radius of 62 metres and this arch dam also rests on winged walls that served as abutments. In the 20th century, the worlds first variable-radius arch dam was built on the Salmon Creek near Juneau, the Salmon Creek Dams upstream face bulged upstream, which relieved pressure on the stronger, curved lower arches near the abutments. The dam also had a toe, which off-set pressure on the upstream heel of the dam. The technology and economical benefits of the Salmon Creek Dam allowed for larger and taller dam designs, the dam was, therefore, revolutionary, and similar designs were soon adopted around the world, in particular by the U. S. Bureau of Reclamation. Pensacola Dam, completed in the state of Oklahoma in 1940, was considered the longest multiple arch dam in the world, designed by W. R. Holway, it has 51 arches. and a maximum height of 150 ft above the river bed. The total length of the dam and its sections is 6,565 ft while the section is 4,284 ft long

18.
Gravity dam
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Gravity dams are designed so that each section of the dam is stable, independent of any other dam section. Gravity dams generally require stiff rock foundations of high bearing strength, the bearing strength of the foundation limits the allowable position of the resultant which influences the overall stability. Also, the nature of the gravity dam structure is unforgiving to differential foundation settlement. Gravity dams provide some advantages over embankment dams, the main advantage being that they can tolerate minor over topping flows as the concrete is resistant to scouring. Large overtopping flows are still a problem, as they can scour the foundations if not accounted for in the design, a disadvantage of gravity dams is that due to their large footprint, they are susceptible to uplift pressures which act as a de-stabilising force. Uplift pressures can be reduced by internal and foundation drainage systems which reduces the pressures, during construction, the setting concrete produces a exothermic reaction. This heat expands the plastic concrete and can take up to decades to cool. When cooling, the concrete is in a state and is susceptible to cracking. It is the task to ensure this doesnt occur. Construction materials of composite dams are the used for concrete. Gravity dams can be classified by plan, Most gravity dams are straight, some masonry and concrete gravity dams have the dam axis curved to add stability through arch action. Gravity dams can be classified with respect to their height, Low. Medium high, between 100 and 300 feet, development of Dam Engineering in the United States. US Committee of the International Commission on Large Dams, Dams of the United States - Pictorial display of Landmark Dams. Denver, Colorado, US Society on Dams

19.
Spillway
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A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically the riverbed of the dammed river itself. In the UK they may be known as overflow channels, spillways ensure that the water does not overflow and damage or destroy the dam. Floodgates and fuse plugs may be designed into spillways to regulate water flow, other uses of the term spillway include bypasses of dams or outlets of channels used during high water, and outlet channels carved through natural dams such as moraines. Water normally flows over a spillway only during flood periods – when the reservoir cannot hold the excess of water entering the reservoir over the amount used. In contrast, a tower is a structure used to release water on a regular basis for water supply, hydroelectricity generation. A spillway is located at the top of the reservoir pool, dams may also have bottom outlets with valves or gates which may be operated to release flood flow, and a few dams lack overflow spillways and rely entirely on bottom outlets. There are two types of spillways, controlled and uncontrolled. A controlled spillway has mechanical structures or gates to regulate the rate of flow and this design allows nearly the full height of the dam to be used for water storage year-round, and flood waters can be released as required by opening one or more gates. An uncontrolled spillway, in contrast, does not have gates, the rate of discharge is controlled only by the depth of water above the reservoirs spillway. Storage volume in the reservoir above the spillway crest can only be used for the storage of floodwater. In an intermediate type, normal level regulation of the reservoir is controlled by the mechanical gates, if inflow to the reservoir exceeds the gates capacity, an artificial channel called either an auxiliary or emergency spillway that is blocked by a fuse plug dike will operate. The fuse plug is designed to over-top and wash out in case of a large flood, the fuse plug concept is used where it would be very costly to build a spillway with capacity for the probable maximum flood. A chute spillway is a common and basic design which transfers water from behind the dam down a smooth decline into the river below. These are usually designed following an ogee curve, most often, they are lined on the bottom and sides with concrete to protect the dam and topography. They may have a device and some are thinner and multiply lined if space. In addition, they are not always intended to dissipate energy like stepped spillways, chute spillways can be ingrained with a baffle of concrete blocks but usually have a flip lip and/or dissipator basin which creates a hydraulic jump, protecting the toe of the dam from erosion. Stepped channels and spillways have been used for over 3,000 years, the steps produce considerable energy dissipation along the chute and reduce the size of the required downstream energy dissipation basin. Research is still active on the topic, with developments on embankment dam overflow protection systems, converging spillways

20.
Flood control
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Flood control refers to all methods used to reduce or prevent the detrimental effects of flood waters. Flood relief refers to methods used to reduce the effects of flood waters or high water levels, Flooding can be exacerbated by increased amounts of impervious surface or by other natural hazards such as wildfires, which reduce the supply of vegetation that can absorb rainfall. Periodic floods occur on many rivers, forming a region known as the flood plain. During times of rain, some of the water is retained in ponds or soil, some is absorbed by grass and vegetation, some evaporates, floods occur when ponds, lakes, riverbeds, soil, and vegetation cannot absorb all the water. Water then runs off the land in quantities that cannot be carried within stream channels or retained in ponds, lakes. About 30 percent of all precipitation becomes runoff and that amount might be increased by water from melting snow, River flooding is often caused by heavy rain, sometimes increased by melting snow. A flood that rises rapidly, with little or no warning, is called a flash flood, flash floods usually result from intense rainfall over a relatively small area, or if the area was already saturated from previous precipitation. Even when rainfall is light, the shorelines of lakes. Coastal areas are flooded by unusually high tides, such as spring tides, especially when compounded by high winds. It damages property and endangers the lives of humans and other species, rapid water runoff causes soil erosion and concomitant sediment deposition elsewhere. The spawning grounds for fish and other wildlife habitats can become polluted or completely destroyed, some prolonged high floods can delay traffic in areas which lack elevated roadways. Floods can interfere with drainage and economical use of lands, such as interfering with farming, structural damage can occur in bridge abutments, bank lines, sewer lines, and other structures within floodways. Waterway navigation and hydroelectric power are often impaired, financial losses due to floods are typically millions of dollars each year, with the worst floods in recent U. S. history having cost billions of dollars. There are many effects of flooding on human settlements and economic activities. However, flooding can bring benefits, such as making soil more fertile, periodic flooding was essential to the well-being of ancient communities along the Tigris-Euphrates Rivers, the Nile River, the Indus River, the Ganges and the Yellow River, among others. The viability for hydrologically based renewable sources of energy is higher in flood-prone regions, some methods of flood control have been practiced since ancient times. These methods include planting vegetation to retain water, terracing hillsides to slow flow downhill. Other techniques include the construction of levees, lakes, dams, reservoirs and this is the method used for remote sensing the disasters

21.
Floodgate
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Floodgate Fund is a venture capital firm based in the United States created by Mike Maples Jr. and Ann Miura-Ko. It was originally named Maples Investments but was renamed Floodgate Fund in March 2010 and it is focused on investments in technology companies in Silicon Valley. Local chores outsourcing platform TaskRabbit, self-storage marketplace SpareFoot, and seasteading platform company Blueseed, Floodgate Fund and Mike Maples have been covered in TechCrunch and Forbes. Mike Maples of Floodgate was also interviewed about his investment philosophy by Sarah Lacy for TechCrunch TV, official website Profile of Floodgate on CrunchBase

Floodgate

22.
Stream
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A stream is a body of water with a current, confined within a bed and banks. Streams are important as conduits in the cycle, instruments in groundwater recharge. The biological habitat in the vicinity of a stream is called a riparian zone. Given the status of the ongoing Holocene extinction, streams play an important corridor role in connecting fragmented habitats, the study of streams and waterways in general is known as surface hydrology and is a core element of environmental geography. Brook A stream smaller than a creek, especially one that is fed by a spring or seep and it is usually small and easily forded. A brook is characterised by its shallowness and its bed being composed primarily of rocks, creek In North America, Australia and New Zealand, a small to medium-sized natural stream. Sometimes navigable by motor craft and may be intermittent, in parts of Maryland, New England, the UK and India, a tidal inlet, typically in a salt marsh or mangrove swamp, or between enclosed and drained former salt marshes or swamps. In these cases, the stream is the stream, the course of the seawater through the creek channel at low. River A large natural stream, which may be a waterway, runnel the linear channel between the parallel ridges or bars on a shoreline beach or river floodplain, or between a bar and the shore. Tributary A contributory stream, or a stream which does not reach the sea, sometimes also called a branch or fork. There are a number of names for a stream. Allt is used in Highland Scotland, beck is used in Yorkshire, Lancashire, Dumfriesshire, Cumbria, Norfolk, and Lincolnshire. Bourne or winterbourne is used in the chalk downland of southern England, brook is used in the Midlands, Lancashire and Cheshire. Burn is used in Scotland and North East England, gill or ghyll is seen in the north of England and other areas influenced by Old Norse. Rivulet is an term encountered in Victorian era publications, stream is used in Southern England. Syke is used in lowland Scotland and Cumbria for a seasonal stream, branch is used to name streams in Maryland and Virginia. Falls is also used to name streams in Maryland, for streams/rivers which have waterfalls on them, little Gunpowder Falls and The Jones Falls are actually rivers named in this manner, unique to Maryland. Kill in New York, Pennsylvania, Delaware, and New Jersey comes from a Dutch language word meaning riverbed or water channel, run in Ohio, Maryland, Michigan, New Jersey, Pennsylvania, Virginia, or West Virginia can be the name of a stream

23.
Levee
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A levee, dike, dyke, embankment, floodbank or stopbank is an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels. It is usually earthen and often parallel to the course of a river in its floodplain or along low-lying coastlines, the word levee, from the French word levée, is used in American English. It originated in New Orleans a few years after the founding in 1718 and was later adopted by English speakers. The name derives from the trait of the ridges being raised higher than both the channel and the surrounding floodplains. The modern word dike or dyke most likely derives from the Dutch word dijk, the 126 kilometres long Westfriese Omringdijk was completed by 1250, and was formed by connecting existing older dikes. The Roman chronicler Tacitus even mentions that the rebellious Batavi pierced dikes to flood their land, the word dijk originally indicated both the trench and the bank. It is closely related to the English verb to dig, in Anglo-Saxon, the word dic already existed and was pronounced as dick in northern England and as ditch in the south. Similar to Dutch, the English origins of the lie in digging a trench. This practice has meant that the name may be given to either the excavation or the bank, thus Offas Dyke is a combined structure and Car Dyke is a trench though it once had raised banks as well. In the midlands and north of England, and in the United States, a dike is what a ditch is in the south, a property boundary marker or small drainage channel. Where it carries a stream, it may be called a dike as in Rippingale Running Dike. The Weir Dike is a dike in Bourne North Fen, near Twenty and alongside the River Glen. In the Norfolk and Suffolk Broads, a dyke may be a ditch or a narrow artificial channel off a river or broad for access or mooring, some longer dykes being named. In parts of Britain, particularly Scotland, a dyke may be a field wall, Levees can be mainly found along the sea, where dunes are not strong enough, along rivers for protection against high-floods, along lakes or along polders. Furthermore, levees have been built for the purpose of empoldering, the latter can be a controlled inundation by the military or a measure to prevent inundation of a larger area surrounded by levees. Levees have also built as field boundaries and as military defences. More on this type of levee can be found in the article on dry-stone walls, Levees can be permanent earthworks or emergency constructions built hastily in a flood emergency. When such a bank is added on top of an existing levee it is known as a cradge

24.
Sluice
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A sluice is a water channel controlled at its head by a gate. A mill race, leet, flume, penstock or lade is a sluice channelling water toward a water mill, the terms sluice, sluice gate, knife gate, and slide gate are used interchangeably in the water and wastewater control industry. A sluice gate is traditionally a wood or metal barrier sliding in grooves that are set in the sides of the waterway, Sluice gates commonly control water levels and flow rates in rivers and canals. They are also used in treatment plants and to recover minerals in mining operations. Sluice gate refers to a gate allowing water to flow under it. When a sluice is lowered, water may spill over the top, usually, a mechanism drives the sluice up or down. This may be a simple, hand-operated, chain pulled/lowered, worm drive or rack-and-pinion drive, flap sluice gate A fully automatic type, controlled by the pressure head across it, operation is similar to that of a check valve. It is a gate hinged at the top, when pressure is from one side, the gate is kept closed, a pressure from the other side opens the sluice when a threshold pressure is surpassed. Vertical rising sluice gate A plate sliding in the vertical direction, radial sluice gate A structure, where a small part of a cylindrical surface serves as the gate, supported by radial constructions going through the cylinders radius. On occasion, a counterweight is provided, rising sector sluice gate Also a part of a cylindrical surface, which rests at the bottom of the channel and rises by rotating around its centre. Needle sluice A sluice formed by a number of thin needles held against a solid frame through water pressure as in a needle dam. The gates of a Guillotine lock work in a way similar to a sluice gate, in the mountains of the United States, sluices transported logs from steep hillsides to downslope sawmill ponds or yarding areas. Nineteenth-century logging was traditionally a winter activity for men who spent summers working on farms, where there were freezing nights, water might be applied to logging sluices every night so a fresh coating of slippery ice would reduce friction of logs placed in the sluice the following morning. Sluice boxes are used in the recovery of black sands, gold. They may be small-scale, as used in prospecting, or much larger, as in commercial operations, typical sluices have transverse riffles over a carpet, which trap the heavy minerals, gemstones, and other valuable minerals. Cast Iron Cast iron has been popular when constructing sluice gates for years and this material is great at keeping the strength needed when dealing with powerful water levels. Stainless Steel Stainless steel in most cases is lighter than the older cast iron material, fibre-reinforced plastic Rather recently a new technologies such as fibre-reinforced plastic are being used to build sluices. This modern technology has many of the attributes as the older ways while bringing in new attributes such as corrosion resistance, in the Somerset Levels, sluice gates are known as clyse or clyce

Sluice
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A sluice gate
Sluice
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Sluice gates near Henley, on the River Thames
Sluice
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A small wooden sluice in Magome, Japan, used to power a waterwheel
Sluice
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Miners working a small sluice on Lucky Gulch, Alaska

25.
Storm surge
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Most casualties during tropical cyclones occur as the result of storm surges. The deadliest storm surge on record was the 1970 Bhola cyclone, the low-lying coast of the Bay of Bengal is particularly vulnerable to surges caused by tropical cyclones. The deadliest storm surge in the twenty-first century was caused by the Cyclone Nargis, the next deadliest in this century was caused by the Typhoon Haiyan, which killed more than 6,000 people in the central Philippines in 2013 and resulted in economic losses estimated at $14 billion. Louis, Diamondhead and Pass Christian in Mississippi, a high storm surge occurred in New York City from Hurricane Sandy in October 2012, with a high tide of 14 ft. The pressure effects of a tropical cyclone will cause the level in the open ocean to rise in regions of low atmospheric pressure. The rising water level will counteract the low pressure such that the total pressure at some plane beneath the water surface remains constant. This effect is estimated at a 10 mm increase in sea level for every millibar drop in atmospheric pressure, strong surface winds cause surface currents at a 45° angle to the wind direction, by an effect known as the Ekman Spiral. Wind stresses cause a phenomenon referred to as wind set-up, which is the tendency for water levels to increase at the downwind shore, intuitively, this is caused by the storm simply blowing the water towards one side of the basin in the direction of its winds. Because the Ekman Spiral effects spread vertically through the water, the effect is proportional to depth. The pressure effect and the wind set-up on an open coast will be driven into bays in the way as the astronomical tide. The Earths rotation causes the Coriolis effect, which bends currents to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. When this bend brings the currents into more contact with the shore it can amplify the surge. The effect of waves, while powered by the wind, is distinct from a storms wind-powered currents. Powerful wind whips up large, strong waves in the direction of its movement, although these surface waves are responsible for very little water transport in open water, they may be responsible for significant transport near the shore. When waves are breaking on a more or less parallel to the beach. The rainfall effect is experienced predominantly in estuaries, Hurricanes may dump as much as 12 in of rainfall in 24 hours over large areas, and higher rainfall densities in localized areas. As a result, watersheds can quickly surge water into the rivers that drain them and this can increase the water level near the head of tidal estuaries as storm-driven waters surging in from the ocean meet rainfall flowing from the estuary. This situation well exemplified by the southeast coast of Florida

Storm surge
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Total destruction of the Bolivar Peninsula (Texas) by Hurricane Ike 's meteotsunamic storm surge in 2008
Storm surge
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Extratropical storm surge model (ETSSM) showing negative water levels, developed bt the National Weather Service. Similar to the SLOSH model, the ETSSM runs off the GFS computer model, and can provide guidance on above or below average water levels in a certain geographical domain as the result of a storm system's influence.
Storm surge
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Hurricane Ike meteotsunamic storm surge damage in Gilchrist, Texas in 2008.

26.
River bifurcation
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River bifurcation occurs when a river flowing in a single stream separates into two or more separate streams which continue downstream. Some rivers form complex networks of distributaries, especially in their deltas, if the streams eventually merge again or empty into the same body of water, then the bifurcation forms a river island. River bifurcation may be temporary or semi-permanent, depending on the strength of the material which separates the distributaries, for example, a mid-stream island of soil or silt in a delta is most likely temporary. A location where a river divides around a rock fin, e. g. a volcanically formed dike, or a mountain, a bifurcation may also be man-made, for example when two streams are separated by a long bridge pier. The Casiquiare canal, which provides a channel between the Amazon and the Orinoco River in Venezuela. Canadas aptly-named Divide Creek splits into two branches near Kicking Horse Pass on the Alberta-British Columbia border, one branch flows west to the Pacific Ocean, the other flows east and eventually reaches the Atlantic Ocean via Hudson Bay. A bifurcation of the Nerodimka River in the city of Uroševac/Ferizaj, Kosovo, was a curiosity as separate streams flowed into the Aegean. The Nerodimka bifurcation was the first hydrological protected object in the former Yugoslavia, the Nerodimka bifurcation is a strict wildlife sanctuary, category I according to IUCN, with an area of 13.0 ha. This bifurcation is considered to be a phenomenon, but created under extremely favorable natural conditions. The former flows west into the Don River and eventually into the Sea of Azov, while the latter flows east, and is lost in the steppe before ever reaching the Caspian Sea. However a dam was built, preventing water from flowing from the Kalaus into the East Manych, the Bahr Yussef is a channel which splits off the west side of the Nile and drains into the Birket Qarun, an inland sea in the Fayum Depression. Originally a natural bifurcation for flood waters, its flow was increased by canalisation in the 12th Dynasty. Around 230BC, the channel of the Nile from which it dried up. In Suriname, the Wayombo and Arrawarra split, the first flowing into the Coppename, the Swedish side of Torne River has a distributary called the Tärendö River, which on average transports 57% of the water of the Torne River into the Kalix River. Bifurcation lake Distributary List of unusual drainage systems Interbasin transfer Notes, References

River bifurcation
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Bifurcation in Hövelhof, Germany
River bifurcation
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River deltas such as the pictured delta of the Salween River in Myanmar often show bifurcations. The water flows in from the lower section of the image and passes on both sides of the large island in the center.

27.
Dams
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A dam is a barrier that impounds water or underground streams. Reservoirs created by not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture. Hydropower is often used in conjunction with dams to generate electricity, a dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. The word dam can be traced back to Middle English, and before that, from Middle Dutch, the first known appearance of dam occurs in 1165. However, there is one village, Obdam, that is mentioned in 1120. The word seems to be related to the Greek word taphos, so the word should be understood as dike from dug out earth. The names of more than 40 places from the Middle Dutch era such as Amsterdam and Rotterdam, early dam building took place in Mesopotamia and the Middle East. Dams were used to control the level, for Mesopotamias weather affected the Tigris. The earliest known dam is the Jawa Dam in Jordan,100 kilometres northeast of the capital Amman and this gravity dam featured an originally 9-metre-high and 1 m-wide stone wall, supported by a 50 m-wide earth rampart. The structure is dated to 3000 BC, the Ancient Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, located about 25 km south of Cairo, was 102 m long at its base and 87 m wide. The structure was built around 2800 or 2600 BC as a dam for flood control. During the Twelfth Dynasty in the 19th century BC, the Pharaohs Senosert III, Amenemhat III, two dams called Ha-Uar running east-west were built to retain water during the annual flood and then release it to surrounding lands. The lake called Mer-wer or Lake Moeris covered 1,700 km2 and is today as Berkat Qaroun. One of the wonders of the ancient world was the Great Dam of Marib in Yemen. Repairs were carried out during various periods, most important around 750 BC and these extensive works were not actually finalized until 325 AD and allowed the irrigation of 25,000 acres. By the mid-late 3rd century BC, an intricate water-management system within Dholavira in modern-day India was built, the system included 16 reservoirs, dams and various channels for collecting water and storing it. Eflatun Pınar is a Hittite dam and spring temple near Konya and it is thought to be from the time of the Hittite empire between the 15th and 13th century BC